The present invention concerns a grinding carrier roller for roll crushing mills, whose axle is retained in a roller mount provided with a barrier air connection and over inner bearings lubricated by splash lubrication and carries a roller hub connected with a roller shell. A measuring sensor reaching into the oil sump is led through a core bore provided in the axle and the end faces of the axle are surrounded by a cover placed respectively on the roller hub and on the roller mount while leaving a gap.
In a known such grinding roller (German Laid-Open Document 2,326,470) the measuring sensor is used for the simultaneous measurement of the oil level and the oil temperature. It consists of a temperature measuring sensor (thermo-couple), the metal sleeve of which is electrically insulated against the bore in the axle. The metal sleeve and the bore form the oppositely lying surfaces of a capacitor, the capacitance of which is varied by the oil which penetrates into the space between the surfaces. The capacitance change is thus a measure of the height of the oil level.
This measuring sensor has proved itself in operation. However, under extreme conditions, for example on the starting up and operation of the mill, difficulties showed themselves in the determination of the oil level. These shall be avoided by the present invention.
Among other objects of the present invention are to provide an arrangement of the foregoing character which is substantially simple in construction and may be economically fabricated.
It is also an object of the present invention to provide an arrangement, as described, which may be readily maintained in service and which has a substantially long operating life.